One of the greatest problems facing wireless network operators is the need to serve large numbers of customers with varying needs using the infrastructure available to them. Historically, a wireless network deployment supported a cell encompassing a relatively large geographic area, with a large base station located in a central area serving user devices distributed through the cell. A cell was historically dedicated to the user devices within its geographic area, with all user devices attached to the cell being served by that base station.
Recent years have brought changes to this historical picture of wireless network deployments. Many small deployments are being created, with smaller base stations serving smaller geographic areas, and with still smaller base stations serving areas that may be, for example, an apartment building a portion of a city block, or even smaller areas. Base stations serving such areas may lie in the same geographic area as that encompassed by a traditional base station, and may serve selected sets of users who may include users separate from those served by those served by the traditional base station or may include a portion of users served by the traditional base station.
Such smaller base stations are naturally easier to deploy in varied locations, and may also be provided at lower cost. Achieving such adaptable and lower cost deployment while meeting performance requirements introduces a number of challenges. In particular, current wireless networking standards, such as 3GPP LTE, or Third Generation Partnership Project-Long Term Evolution, require frequency and phase synchronization. There are a number of techniques for achieving such synchronization for traditional larger base stations, but these techniques may be more difficult to use for the wide variety of smaller base stations that are becoming available.